JPH05183654A - Control method for isdn audio visual terminal equipment - Google Patents

Abstract

PURPOSE:To provide an inexpensive television conference system with convenience of use. CONSTITUTION:Plural AV terminal equipments 22-27 whose frame timing of transmission signals is coincident are connected to a passive bus 21 of an ISDN basic interface so that the users use individually the AV terminal equipments 22-27. The specific AV terminal equipment 22 is used for a master set and the other AV terminal equipments 23-27 are used for slave equipments and reception information is displayed/outputted by all the AV terminal equipments 22-27 and only one AV terminal equipment gets a transmission right at the same time and a transmission signal is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a plurality of ISDN audiovisual terminal devices connected to a passive bus having the same ISDN basic interface.

[0002]

2. Description of the Related Art CCITT (International Telegraph and Telephone Advisory Committee)
Recommendation H. 320 and TTC Recommendation JT-H. The narrow-band videophone / teleconference system and its terminal device (audiovisual terminal device) specified in 320 realize multimedia communication handling a plurality of media such as voice, video, document and image by using ISDN. can do.

In addition, a multipoint control unit (MCU; Multipoint Control) for connecting audiovisual terminal devices currently installed at multiple points to enable a videoconference by integrating them.
Unit), CCITT Recommendation AV. Two
31 standardization works are underway.

FIG. 46 shows an example of a video conference system using this multipoint connection device.

In the figure, the video conference devices 1a, 1a
b, 1c are network control terminal devices 3a, 3b,
3c, and in this case, the video conference devices 1b and 1c are provided in the same house. In addition, the multipoint connection device 4 includes a plurality of network control terminal devices 5 (1)-
It is connected to ISDN2 via 5 (n).

Each of the video conference devices 1a, 1b, 1c sets up a call with respect to the multipoint connection device 4, and establishes an information channel with the multipoint connection device 4. Then, the multipoint connection device 4 exchanges data such as audio, video, documents and images between the connected video conference devices 1a, 1b and 1c.
According to the request from a, 1b, 1c, it exchanges appropriately.

For example, the multipoint connection device 4 divides the display screen of the video data to be output to the video conference device 1a into two, and the video output from the video conference device 1b and the video conference device 1c is displayed on each split screen. As you can see
The video data output from the video conference devices 1b and 1c are combined, the audio data output from the video conference devices 1b and 1c are combined into one audio data, and the combined audio data is output to the video conference device 1a. It also provides the function to do.

Further, the multipoint connection device 4 has a plurality of network control terminal devices 6a and 6a in the ISDN 2 as shown in FIG.
It can also be incorporated into the private branch exchange 7 connected via b. In this case, the video conference devices 1b and 1c
Is connected to the extension side of the private branch exchange 7 via the network terminators 8a and 8b.

In this case, the video conference apparatus 1a, 1
The video conference communication between the b and 1c becomes possible, and the video conference communication between the video conference devices 1b and 1c connected to the private branch exchange 7 becomes possible.

[0010]

However, the following inconvenience arises in the video conference system using such a multipoint connection device.

That is, in the above-mentioned video conference system, one ISDN is provided for each video conference device.
Since a line is required and a multipoint connection device is required, the system cost becomes very large.

Further, considering the progress of the conference, if all the people participating in the conference speak at the same time, the conference will be confused and the proceedings of the conference will be delayed. Proceedings proceed according to the discretion of.

On the other hand, it is natural that such proceedings are also applied to the video conference system, so that there is no situation in which all the terminal devices simultaneously speak during the conference. , The total amount of transmission data per unit time exchanged in the entire system is expected to be considerably smaller than the data transmission capacity per unit time of transmission data possible in the entire system, resulting in poor utilization efficiency of the ISDN line. However, there is a risk that the line cost will unnecessarily increase.

Further, for example, as shown in FIG. 48, one conference table 9 is sandwiched and one video conference device 1 is provided.
0 and multiple seats 11a, 11b, 11c, 11d, 1
Consider a case where 1e and 11f face each other. Further, in this case, the projector 12 is provided on the rear side of the video conference device 10, and the display content of the display device provided in the main body of the video conference device 10 can be enlarged and projected. Further, the video conference device 10 is connected to the ISDN via the network control terminal device 13.

Now, in this case, each seat 11a,
When a person seated at 11b, 11c, 11d, 11e, 11f speaks, it is necessary to point a video camera (not shown) of the video conference apparatus 10 to the speaker.

On the other hand, in the proceedings of the proceedings, a person sitting in the seat 11a and the seat 11f at the end may alternately speak. In this case, the camera angle of the video camera continues from the seat 11a to the seat 11f. And will be shaken.

As described above, when changing the camera angle of the video camera, if a video image in the middle of the change is displayed on the video conference apparatus of the other party, the person watching the screen feels uncomfortable. Occasionally, you may get sick.

In order to prevent such camera sickness, the respective seats 11a, 11b, 11c, 11d,
It is conceivable to provide a video camera for photographing 11e and 11f and switch an effective video camera each time the speaker changes, or to provide a video conference device for each seat.

However, in the former case, it is necessary to construct the video conference apparatus 10 according to the number of participants, and the versatility of the video conference apparatus 10 is lost. In the latter case, the device cost and the line cost of the video conference system become enormous.

Furthermore, when presenting a still image such as characters, figures, and photographs to the other party, the participant must keep looking at the still image display device (for example, the projector 12) provided in the video conference device. There is also a possibility that the participant may be forced to have an unnatural posture, which may cause an unfavorable situation in the man-machine interface.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control method of an ISDN audiovisual terminal device capable of realizing a video conference system at low cost.

[0022]

The present invention is based on the same ISD.
Multiple I's connected to the passive bus of the N basic interface
In a method of controlling an SDN audiovisual terminal device, a transmission signal synchronizing means for synchronizing a transmission signal of each ISDN audiovisual terminal device and a transmission signal of any ISDN audiovisual terminal device are selectively and effectively output to a passive bus. A specific ISDN audiovisual terminal device is equipped with a transmission signal selection means.
While performing the call setup / release procedure with the SDN, each ISDN audiovisual terminal device receives a reception signal through the passive bus and outputs the reception information, while each ISDN audiovisual terminal device receives the reception signal. The ISDN audiovisual terminal device that effectively outputs the transmission signal is selected by the transmission signal selection means based on the transmission request.

In a method of controlling a plurality of ISDN audiovisual terminals connected to a passive bus of the same ISDN basic interface, transmission signal synchronizing means for synchronizing the transmission signals of each ISDN audiovisual terminal and each ISDN audio terminal. A communication means for connecting the visual terminal devices to exchange control information is provided, and a specific ISDN audiovisual terminal device performs a call setup / release procedure with the ISDN, and each ISDN audiovisual terminal device has a passive bus. The ISDN audiovisual terminal device receives the received signal via the SN and outputs the received information, while the specific ISDN audiovisual terminal device effectively outputs the transmitted signal based on the transmission request of each ISDN audiovisual terminal device. Notify each ISDN audiovisual terminals via the communication unit a control signal designating the end device, the designated audiovisual terminal device is obtained so as to enable outputting the transmission signal.

Layer 1 signal control means for separating and integrating reception signals and transmission signals on the ISDN basic interface, and layer 1 signal control by selecting any one of transmission signals output from a plurality of ISDN audiovisual terminal devices. The transmission signal selection means to be output to the means and each IS
A transmission signal synchronizing means for synchronizing a transmission signal of the DN audiovisual terminal device is provided, and a specific ISDN audiovisual terminal device performs a call setup / release procedure with the ISDN, and each ISDN audiovisual terminal device is provided with a layer. While receiving the reception signal output from the 1 signal control means and outputting the reception information,
The ISDN audiovisual terminal device which effectively outputs the transmission signal is selected by the transmission signal selecting means based on the transmission request of each ISDN audiovisual terminal device.

Further, the transmission signal synchronizing means includes the frame data of the transmission signal at a timing when a predetermined delay time has elapsed from the timing of detecting the frame synchronization signal included in the frame data forming the data transfer unit of the reception signal. The output timing of the frame synchronization signal is set.

Further, the transmission signal synchronizing means is a specific ISD.
Delay time detecting means for detecting a delay time based on the difference between the frame sync signal detection timing of the received signal and the output timing of the frame sync signal of the transmitted signal in the N audiovisual terminal device, and other than a specific ISDN audiovisual terminal device In the ISDN audiovisual terminal device, there is provided a delay time setting means for setting the delay time from the frame sync signal detection timing of the reception signal to the output timing of the frame sync signal of the transmission signal to a time corresponding to the detection value of the delay time detection means. It is a thing.

Further, the transmission signal synchronizing means is provided with each I interval at a time interval corresponding to the frame repetition period of the transmission signal.
A synchronizing signal is output to the SDN audiovisual terminal device.

Further, the transmission signal synchronizing means is a specific ISD.
At the frame synchronization timing of the transmission signal output from the N terminal device, ISDN other than this specific ISDN terminal device
The frame synchronization timing of the transmission signal of the terminal device is made to match.

[0029]

Therefore, a video conference system can be constructed by using a plurality of ISDN audiovisual terminal devices connected to the same ISDN basic interface.
The line cost of the entire video conference system can be reduced. Also, since each participant can occupy and use one ISDN audiovisual terminal device, an unfavorable situation that occurs during the proceedings of the proceedings, for example, camera sickness caused by frequent switching of camera angles, Since it is possible to eliminate the need for an unnatural posture for viewing a still image, the usability of the video conference system is improved and the effectiveness of the video conference system is improved.

[0030]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 illustrates one home station of a video conference system according to one embodiment of the present invention.

In the figure, a passive bus 21 of the ISDN basic interface is connected to the network control terminal device 20 connected to the ISDN.
Six audiovisual (hereinafter abbreviated as AV) terminal devices 22, 23, 24, 25, 26, 27 are connected. The terminator 28 is for terminating the passive bus 21.

These AV terminal devices 22, 23, 24,
25, 26, and 27 are TTC recommendation JT-H. It has a terminal function of a narrow band videophone / conference system 320, and is placed on a common conference table 29. Further, six seats 30, 31, 32, 33, 34, 35 are arranged toward the conference table 29 at positions corresponding to the respective AV terminal devices 22, 23, 24, 25, 26, 27, respectively. There is.

AV terminal devices 22, 23, 24, 25, 2
Since 6,27 are lightweight and small, the seats 30, 31, 32,
Participants of the conference seated at 33, 34, and 35 can appropriately adjust the screen of each AV terminal device 22, 23, 24, 25, 26, and 27 and the direction of the video camera (not shown) so that they can use it easily. Can be adjusted to.

Now, these AV terminal devices 22, 23,
Reference numerals 24, 25, 26, and 27 are terminal devices that use ISDN as a transmission path. FIG. 2A shows a call control in a circuit switching mode performed by the terminal devices connected to the ISDN with the ISDN. An example of the procedure is shown.

That is, the calling terminal first sets the circuit switching mode as the transfer mode, sends a call setting message SETUP with the destination terminal designated as a destination to the ISDN to request call setting with the called terminal, and ISDN. Sends a call setup message SETUP to the designated destination terminal to make a call. The ISDN also sends a call setting acceptance message CALL_PROC for notifying the call setting status to the calling terminal.

Upon detection of an incoming call, the called terminal sends a call message ALERT to ISDN when the called terminal is ready to receive a call, and the ISDN sends a call message ALERT to the calling terminal to call the called terminal. Notify that it has started.

When the called terminal responds to the incoming call, it sends a response message CONN to the ISDN, and the ISDN sends a response message CONN to the calling terminal to notify that the called terminal has accepted the call.

The ISDN also sends a response confirmation message CONN_ACK to the destination terminal to confirm the response of the destination terminal, and at that time, an information channel (B channel) for data transmission between the source terminal and the destination terminal. Is established.

As a result, the data transmission using the information channel is executed between the source terminal and the destination terminal according to the transmission control procedure set in the transmission function of each terminal.

When the data transmission is completed, the calling terminal sends a disconnection message DISC to ISDN to request the release of the information channel, and ISDN releases the release message R.
EL is sent to the calling terminal to notify the restoration of the information channel. On the other hand, the ISDN sends a disconnection message DI to the destination terminal.
SC is sent to request the release of the information channel, and the destination terminal sends a release message REL to ISDN to notify the restoration of the information channel.

As a result, the calling terminal IS sends the release completion message REL_COMP notifying the completion of the channel disconnection.
In response to the DN, the information channel between the calling terminal and the ISDN is released. At the same time, the ISDN sends a release completion message REL_COMP to the destination terminal,
The information channel between N and the called terminal is released. As a result, the information channel established between the calling terminal and the called terminal is completely released.

In this way, the information channel is set between the calling terminal and the called terminal, data transmission is performed, and when the data transmission is completed, the information channel is released.

Further, each message for ISDN call setup is, as shown in FIG. 3 (a), a protocol specification (format, format,
Protocol identifier to identify the sequence, etc.)
Call number to identify which call the message pertains to, message type to identify the content of each message, mandatory information elements that must be added to each message, and each message It consists of additional information elements added as required. Note that 0, 1, or a plurality of essential information elements are set according to the message type, and 0, 1, or a plurality of additional information elements are arranged according to the situation.

The call setup message SETUP is, as shown in FIG. 7B, a "transmission capability" as an essential information element.
And the additional information element is, for example, "calling number",
It has information elements such as "Called number", "Called sub-address", "Lower layer compatibility", "Higher layer compatibility", and "User-user".

An outline of these information elements will be described.

The "transfer capability" information element is an information transfer indicating whether the content of the information to be transmitted is voice, unrestricted digital information, restricted digital information, 3.1 KHz audio, 7 KHz audio, or video. Capability, transfer mode indicating whether the switching function used is circuit switching or packet switching, information transfer speed indicating information transfer speed, information indicating information transfer mode, and information indicating user information protocol, etc. Consists of.

The "calling number" information element is the ISDN of the calling terminal.
Represents the number and the "Called Number" information element is the IS of the called terminal.
Indicates the DN number. The "Destination Sub Address" information element is
This is for identifying the intended terminal of up to eight terminals connected to the same home wiring (passive bus) on the destination side.

The "lower layer compatibility" information element is for use in the communication possibility check with the partner terminal, and its basic contents are the same as the "transmission capability" information element. Further, this "low layer compatibility" information element has more detailed contents (for example, CCITT recommendation H.221 function).
Is included.

The "higher layer compatibility" information element is used for consistency check with the partner terminal. For example, group 2 / group 3 facsimile, group 4
The terminal function of the facsimile, mixed mode, teletex, videotex, telex, message handling system, or AV is displayed.

The "user-user" information element is intended to be used for the communication of information between users, the content of this "user-user" information element being transferred transparently without being interpreted by the ISDN. It is transmitted to the other user.

Now, in the AV terminal device, in the B channel, the TTC recommendation JT-H. Data is exchanged in the multi-frame format defined by 221.

As shown in FIG. 4, one multi-frame MFL includes eight sub-multi-frames SMF1 to SMF.
8 sub-multiframes SMF1 to 8
Each SMF 8 is composed of two frames. That is, one multi-frame MFL is composed of 16 frames FLM0 to FLM15.

Each frame FLM0 to FLM15
As shown in FIG. 5, it is composed of data of 80 octets, and the respective bit positions in which these octets are arranged in the bit order form subchannels SCH1 to SCH8.

The 8th bit of the 1st octet to the 8th octet is the frame synchronization signal (Frame Ali).
The 8th bit of the 9th octet to the 16th octet constitutes a bit rate allocation signal (Bit rate Allocation).
Signal) BAS. That is, the sub-channel SCH8 is assigned to the eighth bit of the 17th octet to the 80th octet, and this portion is applied to the application channel AC (Application Channel).
el) is sometimes called. Also, sub-channel SC
In the 17th to 24th octets of H8, data of an encrypted channel for exchanging key information for encrypting data may be set (optional).

In this way, the frame synchronization signal FAS
8 bits are arranged in one frame FLM1 to FLM16, and the bit allocation is configured in units of multi-frame MFL as shown in FIG.

That is, even frames FLM0, FLM
2, ..., The second to eighth octets of the FLM 14, and the odd frames FLM1, FLM3 ,.
A horizontal synchronization signal composed of an 8-bit data pattern of "001101011" is arranged in the FLM 15, and a vertical synchronization composed of a 6-bit data pattern of "001011" is arranged in the first octet of the odd-numbered frames FLM1, FLM3, ..., FLM11. A sync signal is placed.

By detecting the horizontal synchronizing signal and the vertical synchronizing signal, the synchronization of one multi-frame MFL can be detected.

The 0th frame, the 2nd frame, the 4th frame
Bits N1, N2, N3, N4, N5 of the first octet of the frame, the sixth frame and the eighth frame are used to indicate the multi-frame number. Of these, the bit N5 is used to indicate whether or not the multiframe number is used. Thus, since the data used for the multiframe number is 4 bits, the multiframe number changes in descending order with a value of 0 to 15, and the same multiframe number appears every 16 multiframes.

The tenth frame, the twelfth frame,
And bit L of the 1st octet of the 13th frame
1, L2, L3 are used to display the connection number indicating the order in which the information channels carrying the frame among the currently used information channels are connected. The bit R of the 1st octet of the 15th frame is reserved (reserved) for future recommendation and 0 is set.

The bit TEA of the first octet of the 14th frame is used to indicate that data transmission is not possible due to an internal failure of the data terminal device.

Also, odd-numbered frames FLM1, FLM3
.., bit A of the third octet of the FLM 15 is used to indicate whether frame synchronization or multi-frame synchronization is established or out of synchronization.

Also, odd-numbered frames FLM1, FLM3
..., bit C1 of the fifth octet, sixth octet, seventh octet, and eighth octet of FLM15
C2, C3 and C4 are for displaying a CRC (Cyclic Redundancy Check) code that is referred to for data error detection (that is, channel quality detection) of two consecutive frames (that is, sub-multiframe). , And the bit E of the fourth octet of the odd frames FLM1, FLM3, ..., FM15 is used to indicate that a transmission error has been detected on the receiving side.

The bit rate allocation signal BAS is, as shown in FIG. 7, even-numbered frames FLM0, FLM2,
.., FLM14, 8-bit data representing the capability BAS or BAS command is arranged, and in the subsequent odd numbered frames FLM1, FLM3 ,.
A double error correction code for error correcting the value of the capability BAS or BAS command transmitted in the immediately preceding frame is arranged.

Data transmission of the multi-frame MFL is performed in the order of frame numbers, and each frame FLM0 to FLM15 is transmitted in the octet order from the first octet to the 80th octet, as shown in FIG. The first bit of the octet is sent first.

That is, each of the frames FLM0 to FLM0
In the FLM 15, the first bit of the first octet is transmitted first and the eighth bit of the 80th octet is transmitted last.

FIG. 9 shows A using two information channels.
An example of a transmission procedure when exchanging audio data and moving image data between V terminal devices is shown. This transmission procedure is based on TTC Recommendation JT-H. 242 and Recommendation JT-
H. Follow 320.

First, the calling terminal makes a call to the destination terminal and performs a call setup procedure on the signaling channel to secure one information channel (hereinafter referred to as the first channel) (Phase A). Frame synchronization is performed while exchanging frame data in which PCM audio data (A-law or μ-law, 64 Kbps) is set on one channel (frame mode), and when frame synchronization is established, the capability BAS data and command BAS data are mutually exchanged. Exchanges (phase B1-1), decides a transmission mode to be used at that time, and initiates an additional call setup request for securing the second information channel (phase B1-2).

Then, from the contents of the exchange of the transmission modes at that time, the common and highest function mode is selected (phase B1-3), and the calling terminal functions as the called terminal in the selected operation mode. A BAS command designating a terminal function is operated to operate, and parameters common to the device functions of the calling terminal and the called terminal are set (phase B2). Thereby, in the first channel, for example, data transmission of audio data (16 Kbps) and data transmission of moving image data (46.4 Kbps) corresponding to the transmission mode selected at that time are performed (phase C). ..

When the first channel starts data transmission in the frame mode, the call setup procedure is performed on the signaling channel for the second information channel (hereinafter referred to as the second channel) (phase CA), and the second channel is established. Then, frame data including only the frame synchronization signal FAS and the bit allocation signal BAS is exchanged using the second channel to establish frame synchronization and multi-frame synchronization (phase CB1-11), and then the first channel and the second channel. Establish synchronization between channels (Phase CB1-1
2).

When the synchronization of the two information channels is completed,
The BAS command is sent from the calling terminal side to set the transmission mode (phase CB1-2), the transmission mode is switched to the set contents (phase CB1-3), and the common parameter is set (phase CB3).

In this way, when the initialization of the second channel is completed, after that, two pieces of frame data exchanged in the first channel and two pieces of frame data exchanged in the second channel are synchronized with each other. Using the information channel, the audio data and the moving image data are data-transmitted at the transmission rates of 48 Kbps and 76.8 Kbps, respectively.

To end such data transmission, first, the second channel is disconnected. At this time, the first
For voice data transmission on the channel only, the procedure for setting the common mode is performed (Phase CD
1), the mode of the second channel is switched to the frame mode 0F (phase CD2). At this time, the first channel and the second channel are asynchronous, and the second channel is in a state where the call is held in the transmission state of only the frame synchronization signal FAS and the bit allocation signal BAS, and the call disconnection of the signal channel is performed. The call for the second channel is ready to be released by the release procedure.

In the first channel, phase CD1
During the phase CD2, the audio data and the moving image data are transmitted at the total transmission rate of 62.4 Kbps in the frame mode. Further, when the operator of one terminal ends the call, the transmission of the moving image data is ended. All the transmission capacities of the first channel including the transmission capacity of the moving image data are switched to the mode 0F in order to use for the voice transmission (phase D2), and then the call disconnection release procedure of the signal channel is used to call the first channel Is ready to be released.

As a result, the call disconnection release procedure is executed on the signaling channel for the first channel and the second channel (phase E), and the AV transmission between the two terminals is completed.

As described above, the AV terminal first secures one information channel (first channel) to establish the frame mode and then secures the second information channel (second channel) to secure the frame mode. And the frame mode synchronized by the two information channels is established, the audio data and the moving image data are exchanged.

Further, when the data transmission is finished, it is necessary to once change from the mode in which the transmission path in which both the first channel and the second channel are synchronized is used to the mode in which only the first channel is used. is there. Therefore, first, each encoding rule of audio data and moving image data is set to a method that optimizes the transmission capacity of the first channel of 62.4 Kbps, and the transmission mode of only the first channel is changed, while the second channel is , The synchronous state with the first channel is stopped, the mode is changed to the mode 0F in which the user data is in the idle transmission state, and the call is disconnected / released by the call disconnection / release procedure of the signal channel. Also, the first channel disconnects / releases the call by the call disconnection release procedure of the signal channel after changing from two types of media transmission of audio data and moving image data to mode 0F which is a transmission mode of only audio data. .. It should be noted that the first channel does not switch the mode to two types of media transmission of audio data and moving image data but directly changes the mode to the mode 0F and then disconnects the call.
It can also be released. In addition, the billing information obtained in the call disconnection / release procedure is managed for each channel.

Now, the AV terminal devices 22, 23, 24, 25, 26, 27 connected to the passive bus 21 are, as shown in FIG. 10, one master AV (audiovisual).
It is divided into a terminal device MSR and other slave AV (audiovisual) terminal devices SLV1 to SLVm (in this case, m = 5; see FIG. 1). Where:
Master AV terminal MSR and slave terminal SLV1
All or part of SLVm is called a home station, and an AV terminal device or multipoint connection device that is a communication partner is called a partner station.

This master AV terminal device MSR performs a call setting operation for establishing two information channels with a partner station for making a video conference, a frame synchronization of the information channels, and a call disconnection release operation. The slave AV terminal devices SLV1 to SLVm receive a reception signal from the passive bus 21, output the contents to the output device of their own terminal, and transmit the right of transmission. When (described later) is obtained, the input data obtained from the input device of the own terminal is converted into the data of the format corresponding to each input device, and the data is sent to the passive bus 21.

At this time, only one of the master AV terminal MSR and the slave AV terminals SLV1 to SLVm connected to the passive bus 21 can send a transmission signal to the passive bus 21, In this embodiment, an operator operates an input device (described later) provided in each of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm.
The right to send a transmission signal (hereinafter referred to as the transmission right) can be set in any of the terminal devices.

Since the transmission signal needs to hold the frame synchronization state established with the partner station, in the present embodiment, the master AV terminal device MSR and the master AV terminal device MSR and Slave AV terminal devices SLV1 to S
The transmission signal of LVm is made to hold the same frame state.

That is, first, the master AV terminal device M
In all of the SR and the slave AV terminal devices SLV1 to SLVm, when a predetermined delay time elapses after receiving the multiframe of the multiframe number “0” of the reception signal, the multiframe number “0” of the transmission signal is received. By forming the transmission timings of the multi-frames, the frame synchronization states of the transmission signals of the respective terminal devices are matched.

When the operator's operation detects that the terminal has acquired the transmission right, and when it is detected that the terminal abandons the transmission right, the first operation is performed from the timing at which the operation is detected. At the timing of the transmission signal of the multi-frame number “0”, the terminal device that has detected the acquisition of the transmission right starts the output of the transmission signal, and the terminal device that has detected the abandonment of the transmission right ends the output of the transmission signal.

As a result, even when the transmission right is transmitted and received between the two terminal devices, the partner station can receive the frame data of consecutive multi-frame numbers. The frame synchronization state between them is maintained, and stable data communication operation can be performed.

When the transmission right is exchanged between two terminal devices in a state where the frame synchronization states of the two terminal devices connected to the same passive bus are the same,
To maintain the frame synchronization status with the other station,
Frame synchronization signal FAS and bit rate allocation signal BAS
Therefore, the transmission signals may be switched in sub-multiframe units (see FIG. 11).

Therefore, as described above, even when the transmission signal is switched at the timing of the multiframe number "0", the frame synchronization state with the partner station can be maintained.

FIG. 12 shows a master AV terminal device MSR and slave AV terminal devices SLV1 to SLVm (hereinafter referred to as A
(Generally referred to as a V terminal device).

In the figure, the transformer 40 is for connecting the signal of the passive bus 21 connected via the socket 41 to an alternating current, and the other connection end is connected to the bus interface circuit 42.

The bus interface circuit 42 separates the reception signal of the passive bus 21 and outputs it to the layer 1/2 control device 43, and sends the transmission signal output from the layer 1/2 control device 43 to the passive bus 21. Is what
The layer 1/2 control device 43 performs signal control of layers 1 and 2 of the ISDN basic interface, and separates / integrates signals of two information channels and one signal channel multiplexed in transmission / reception signals. And the signal on the signal channel is exchanged with the D channel layer 3 control unit 44.
The signals on one information channel are multiplexed / demultiplexed by the control unit 4
It is exchanged with 5.

Here, from the layer 1/2 control device 43 to the multiplexing / demultiplexing control device 45, the reception signal RD1 of the B1 channel, the reception signal RD2 of the B2 channel, the reception signal RD.
1, a bit clock CPb representing the bit timing of RD2 and an octet clock CPo representing the octet timing of the reception signals RD1 and RD2 are output, and the multiplexing / demultiplexing control device 45 outputs the layer 1
/ 2 control device 43, the transmission signal TD of B1 channel
The 1 and B2 channel transmission signals TD2 are output.

The D channel layer 3 control section 43 uses the ISD
This is for exchanging data between the call control unit 46 that performs the call control procedure processing with the N and the layer 1/2 control device 43 (interface means).

The multiplexing / demultiplexing controller 45 receives the received signal R
The audio data, the video data, and the two general-purpose data multiplexed in D1 and RD2 are separated and output to the audio CODEC 47, the video CODEC 48, and the external device, respectively, and the audio CODEC 47, the video CODEC 48, and the external device. The audio data, the video data, and the two general-purpose data respectively input from the device are incorporated into frame data of a predetermined format, and the transmission signals TD1 and TD2 of the frame data are output to the layer 1/2 control device 43. Further, the synchronization signal SYC is output for the terminal device that processes general-purpose data.

The multiplexing / separation control unit 49 inputs the frame synchronization signal FAS and the bit rate allocation signal BAS detected by the multiplexing / separation control device 45, and controls the operation mode of the multiplexing / separation control device 45. It is for.

The voice CODEC 47 mutually converts a voice signal and voice data in accordance with a predetermined conversion rule, and the connection end on the voice signal side is switched by the switch 50 to the handset 51 for communication and various types of communication. A tone generator 52 for outputting a tone signal, or 2
The / 4 line conversion section 53 is switched and connected to either of the 4 line side input terminals. A group 3 facsimile apparatus 54 for transmitting and receiving a document image is connected to the 2 line side input end of the 2/4 line converting portion 53.

The video CODEC 48 mutually converts a video signal and video data according to a predetermined conversion rule, and the video signal output terminal is added to the video monitor device 56 via the video output circuit 55. As a result, an image corresponding to the received video data is displayed on the video monitor device 56. Further, the video signal output from the video camera device 57 for inputting an image is supplied to the video CODE via the video input circuit 58.
It is added to the video signal input terminal of C48.

The input device 59 is used by the operator to operate the AV terminal device, and includes a ten-key pad for dial input, a terminal switching key for inputting acquisition / abandonment of the transmission right, and various other types. Function keys of which the operation signal is applied to the system control unit 60. The system control unit 60 controls the operation of the AV terminal device, and the display device 61 displays various control information such as information indicating the terminal state from the AV terminal device to the operator. belongs to.

The power supply device 63 forms a DC power supply from a commercial power supply, and the switching device 64 is
This is for selecting the DC power output from the power supply device 63, and at the time of power failure, selecting the DC power supplied from the phantom power supply from the station line and supplying the selected DC power to the DC / DC converter 65. , DC / DC
The converter 65 receives this AV power from the applied DC power supply.
It is for forming various DC power supplies required for the terminal device.

The portion surrounded by the chain double-dashed line in FIG.
It is a part that can be operated by a DC power supply supplied from the DC / DC converter 65 even during a power failure.

Therefore, in this AV terminal device, a call operation using the handset 51, a still image transmitting / receiving operation using the group 3 facsimile device 54, and a video information transmitting / receiving operation using the video monitor device 56 and the video camera device 57. It is possible to perform a call operation and a video information transmission / reception operation at the same time, and a still image transmission / reception operation and a video information transmission / reception operation can be performed at the same time.

Further, general-purpose data can be used to perform data transmission between other data terminal devices such as personal computers and telewriting terminals.

FIG. 13 shows an example of the multiplexing / demultiplexing control device 45.

In the figure, the bit clock CPb and the octet clock CPo are added to a synchronization control unit 70 for controlling the operation of each unit of the multiplexing / demultiplexing control unit 45. The reception signals RD1 and RD2 are added to the loopback unit 71, and the transmission signals TD1 and TD are also added.
2 is output to the external device via the loopback unit 72.

The loopback unit 71 selectively adds the reception signals RD1 and RD2 to the loopback unit 72 or the synchronization units 73 and 74 based on the control signal from the synchronization control unit 70. 74 extracts the frame synchronization signal FAS included in the input reception signals RD1 and RD2 to detect / hold the frame / multi-frame synchronization and outputs FAS data DDf representing the content of the frame synchronization signal FAS to an external device. .. Also, the bit rate allocation signal BAS is extracted from the input reception signals RD1 and RD2, and the BAS data D representing the contents thereof is extracted.
Db is output to the BAS decoder 75. Further, when the frame synchronization is maintained, the received signal RD
Received frame data is extracted from the first and RD2 and output to the data buffers 76 and 77, respectively.

When the synchronization units 73 and 74 detect the multi-frame number "0", the multi-frame detection signal D
D1 is generated, and this multi-frame detection signal DD1 is
The signal is delayed by the delay circuit 78 for a time corresponding to n bits of the bit clock CPb and added to the data multiplexing unit 79 as a multi-frame timing signal DDm.

Further, the synchronizing units 73 and 74 form a frame synchronization signal at the extracted frame timing, form a multiframe synchronization signal at the extracted multiframe timing, and generate the frame synchronization signal and the multiframe synchronization signal ( (Including multi-frame number)
Is output to the synchronization control unit 70 and the multi-frame synchronization signal is output to the inter-channel synchronization unit 80. Further, the synchronization units 73 and 74 output the synchronization signal SYC at the frame synchronization timing.

The BAS decoder 75 uses the BAS data DD
b is converted into corresponding internal data, and the converted data is received BA through the BAS buffer 81.
It is output to the external device as S data DDb '.

The inter-channel synchronizing section 80 is the synchronization control section 70.
In accordance with the input frame synchronization signal and multi-frame synchronization signal in a state of being synchronized with the clock signal added from, the multi-frame number of the received frame data of the B1 channel added via the data buffer 76 and the data buffer 77. This is for aligning the synchronization shift of the received frame data in multiframe units so that the multiframe numbers of the received frame data of the B2 channel to be added match, and in the B1 channel aligned in the multiframe units. Received frame data FD1 and received frame data F of B2 channel
D2 is added to the channel switching unit 82.

The channel exchanging unit 82 receives the B1 signal when the channel exchanging command is output from the synchronization control unit 70.
The reception frame data FD2 is output as the reception frame data FD1a of the channel, the reception frame data FD1 is output as the reception frame data FD2a of the B2 channel, and when the channel exchange command is not output from the synchronization control unit 70, reception is performed. The frame data FD1 is output as the reception frame data FD1a, and the reception frame data FD2 is output as the reception frame data FD2a. The received frame data FD1a and FD2a are added to the data separation unit 83.

The timing data generator 84 generates timing data TTb for data separation based on a control signal SS1 input from an external device and outputs the timing data TTb to the data separator 83 as well as data multiplexing. The timing data TTg is generated and output to the data multiplexing unit 79.

The data separation section 83 synchronizes with the clock signal applied from the synchronization detection section 70, and based on the timing data TTb, the received frame data FD1a, FD2.
From a, receive audio data ODr, receive video data VD
r and reception general-purpose data PDra and PDrb are extracted, and reception audio data ODr, reception video data VDr, and reception general-purpose data PDr of these are extracted.
It outputs a, PDrb to an external device.

The BAS encoder 85 is a transmission BA corresponding to the transmission BAS data DDba added from the external device.
The S signal SS2 is formed, and the transmission BAS signal SS2 is added to the data multiplexing unit 79.

The data multiplexing unit 79 synchronizes with the clock signal added from the synchronization detecting unit 70, and based on the timing data TTg, the transmission audio data ODt, the transmission video data VDt, and the transmission general-purpose data added from the external device. PDta and PDtb are multiplexed to form transmission frame data FT1a for the B1 channel and transmission frame data FT2a for the B2 channel.

At the same time, the data multiplexer 79 sends the transmission BAS signal SS2 to the respective frame data FT1.
a and FT2a are assigned to the bit rate allocation signals BAS, and the transmission FAS signal SS3 input from the synchronization control unit 70 is transmitted to the respective frame data FT1a and FT2a.
The frame synchronization signal FAS is arranged at the corresponding bit position. Further, regarding the CRC bits included in the bit rate allocation signal BAS and the frame synchronization signal FAS,
They are formed inside the data multiplexing unit 79 and their CRC is
Bits are placed in corresponding bit positions of the frame sync signal FAS and the bit rate allocation signal BAS, respectively.

Then, the data multiplexing unit 79 outputs the formed transmission frame data FT1a, FT2a to the channel switching unit 86 when the transmission permission signal SS4 is output from the synchronization detection unit 70. In addition, the synchronization detection unit 70
When the transmission permission signal SS4 is not output from
The transmission frame data FT1a and FT2a are not output to the channel switching unit 86.

When the channel exchange command is output from the synchronization control unit 70, the channel exchange unit 86 outputs the transmission frame data FT2a as the transmission frame data FT1 of the B1 channel and the transmission frame data FT2 of the B2 channel. Frame data FT
1a is output, and when the channel exchange command is not output from the synchronization control unit 70, the transmission frame data FT1a is output as the transmission frame data FT1 and the transmission frame data FT2a is output as the transmission frame data FT2. These transmission frame data FT1 and FT2 are output to the external device as transmission signals TD1 and TD2 via the loopback unit 72.

When the loopback command signal SS5 is output from the synchronization control unit 70, the loopback unit 72 loops back the reception signals RD1 and RD2 output from the loopback unit 71 as transmission signals TD1 and TD2. Send out.

Therefore, when the receiving operation is started, the reception signals RD1 and RD2 are added to the synchronizing units 73 and 74 via the loopback unit 71, whereby the synchronizing unit 73,
The frame synchronization detection operation of the frame data of the reception signals RD1 and RD2 is performed by 74.

When the synchronization detection state is entered, the synchronization units 73 and 74
14, the multi-frame detection signal DD1 is output at the timing at which the multi-frame number "0" is detected, whereby the delay circuit 78 outputs n bits of the bit clock CPb from the output timing.
The multi-frame timing signal DDm is output to the data multiplexing unit 79 at the timing when the time corresponding to the bits has passed.

Since the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm receive the same received signal, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLV respectively.
The multiplex / separation controller 45 of m detects the multi-frame number "0" at the same timing, and therefore the multiplexer / separation controller 45 of each master AV terminal MSR and slave AV terminals SLV1 to SLVm.
Then, the multi-frame timing signal DDm is output at the same timing.

As a result, the transmission timings of the multi-frame number "0" of the transmission signals TD1 and TD2 are the same in all of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm. The frame timings of the transmission signals TD1 and TD2 in the device MSR and the slave AV terminal devices SLV1 to SLVm are the same.

FIG. 15 shows an example of processing performed by the master AV terminal device MSR at the start of transmission.

First, the master AV terminal device MSR sets the multiplexing / demultiplexing control device 45 in the transmission permitted state, and executes the call setting procedure for making a call to the partner station (process 11).
0), after establishing the first channel (process 111) and after establishing frame synchronization on the first channel (process 112),
Data transmission using the first channel is started (process 11).
3).

Then, the additional call setting procedure is executed (process 1
14), establishing a second channel (process 115),
After establishing frame synchronization on the channel (process 11
6), start data transmission using the second channel (process 117).

In this way, first, with the master AV terminal device MSR having the transmission right, two information channels are established with the partner station, and data transmission using the two information channels is performed. Be seen.

FIG. 16 shows the slave AV terminal device SLV1.
~ SLVm shows the processing performed at the start of transmission.

First, the slave AV terminal devices SLV1 to SLV
When instructed to start the data communication, the LVm sets the multiplexing / demultiplexing control device 45 in the transmission non-permission state and performs only the receiving operation.

Next, the master AV terminal device MSR performs a call setting operation for establishing the first channel,
When the channel is established, the reception signal of the first channel is obtained, so the frame synchronization detection / establishment operation of the reception signal RD1 is performed for the first channel (process 121).

Thus, the slave AV terminal device SLV
1 to SLVm start the reception operation of the same reception signal as the master AV terminal device MSR for the first channel (process 122).

Then, the master AV terminal device MSR performs an additional call setting operation for establishing the second channel,
When the second channel is established, the received signal of the second channel is obtained, and therefore the received signal RD2 of the second channel is obtained.
The frame synchronization detection / establishment operation is performed (process 12).
3).

Thus, the slave AV terminal device SLV
1 to SLVm start the reception operation of the same reception signal as the master AV terminal device MSR for the second channel (process 124).

In this way, the slave AV terminal device S
At the start of transmission, LV1 to SLVm are in a mode for monitoring the reception signals RD1 and RD2 of the first channel and the second channel, and the same audio and video as the master AV terminal device MSR are displayed and output.

In this way, when the data transmission is started, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm perform the processing shown in FIG.
Acquire / abandon the transmission right.

That is, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm monitor that the operator operates the terminal switching key of the input device 59 (decision 131), and the operator operates the terminal switching key. If the result of judgment 131 is YES,
Immediately before that, the transmission disabled state is set, and it is determined whether or not the transmission right has been acquired by the terminal switching key (determination 132).

When the terminal switching key is operated in the state where the transmission disabled state is set, the result of judgment 132 is YE.
When S is reached, the transmission permission state is set in the multiplexing / demultiplexing control device 45 (process 133), the data transmission operation by the own terminal is set, and the process returns to the determination 131.

Further, when the terminal switching key is operated in the state where the transmission permitting state is set and the result of the determination 132 is NO, the transmission disable state is set in the multiplexing / demultiplexing control device 45 ( (Process 134), a state in which the data transmission operation by the own terminal cannot be performed, that is, the own terminal is set to the monitor mode, and the process returns to the determination 131.

Therefore, in the data communication state, for example,
Further, when the transmission right is transferred from the master AV terminal device MSR to the slave AV terminal device SLV1, the operator of the master AV terminal device MSR and the slave AV terminal device SL.
The operator of V1 operates the terminal switching key of the input device 59 at an appropriate timing.

Thus, for example, as shown in FIG.
As shown in (b) and (c), the master AV terminal device MS
In the R and slave AV terminal devices SLV1, the operation timings of the terminal switching keys occur at the timings of the multiframe number "3" and the multiframe number "1", respectively.

As a result, the transmission disable state is set in the multiplexing / separation control unit 45 of the master AV terminal MSR at the timing of the multiframe number "3", and the multiplexing / separation control unit of the slave AV terminal SLV1. In 45, the transmission permission state is set at the timing of the multiframe number “1”.

As a result, the synchronization control unit 70 of the multiplexing / separation control unit 45 of the master AV terminal device MSR allows the transmission permission output to the data multiplexing unit 79 at the timing of the next multiframe number "0". The signal SS4 is stopped, and the synchronization control unit 70 of the multiplexing / demultiplexing control device 45 of the slave AV terminal SLV1 sends the transmission permission signal SS4 to the data multiplexing unit 79 at the timing of the next multiframe number “0”. Is output.

As a result, as shown in FIG. 10D, the contents of the transmission signal output to the passive bus 21 at the timing of the multi-frame number "0" is changed from the transmission signal of the master AV terminal device MSR. , Slave AV terminal device S
The slave AV terminal device S is switched to the transmission signal of LV1.
The LV1 operator will be able to communicate with the partner station.

Also, from the slave AV terminal SLV1 which has acquired the transmission right to another slave AV terminal SLV2.
The same operation is performed when the transmission right is passed to the SLVm or the master AV terminal device MSR, and the acquisition / abandonment of the transmission right is appropriately performed.

Here, when the B channel is used, since the transmission time of one data frame is 10 milliseconds, 1
The transmission time of one multiframe is 160 milliseconds, and the 16 multiframe interval is 2.56 seconds. Therefore, in the case of this embodiment, the maximum time delay required for the transmission right to be actually transferred after the operator gives the transmission right is 2.56 seconds.

As described above, in this embodiment, the master AV
Terminal device MSR and slave AV terminal devices SLV1 to SLV1
Since the operator who uses the SLVm can appropriately speak with the right to speak, the conference can proceed smoothly.

Further, since a plurality of people can participate in the conference by using one ISDN basic interface,
The number of ISDN lines required for constructing a video conference system is significantly reduced, and a video conference system with a low line cost can be realized.

Further, each master AV terminal device MS
R and the slave AV terminal devices SLV1 to SLVm are
Since it can be realized with almost the same configuration as the videophone terminal, the device cost of the entire system can be reduced.

Also, since the camera angle does not change when the speaker changes, the image of the state in which the camera angle is being changed is not displayed on the video conferencing device of the other party, so that it causes camera sickness. It is possible to prevent the participants of the conference from feeling uncomfortable without causing such a situation.

By the way, in the above embodiment, the master A
V terminal device MSR and slave AV terminal device SLV1
~ In order to match the frame synchronization state of the transmission signal of SLVm, the timing of the multi-frame number "0" of the transmission signal is formed with reference to the timing of the multi-frame number "0" of the reception signal. The method of matching the frame synchronization states of is not limited to this.

For example, the time difference between the multi-frame number "0" of the received signal and the multi-frame number "0" of the transmitted signal in the master AV terminal device MSR is detected, and the multi-frame number "0" of the slave AV terminal devices SLV1 to SLVm is detected. , And the time difference between the multi-frame number “0” of the transmission signal and the detected time difference, the master AV terminal MSR and the slave AV terminal S
It is possible to match the frame synchronization states of the transmission signals of LV1 to SLVm.

FIG. 19 shows the master A in such an embodiment.
The structural example of the multiplexing / separation control apparatus 45 of the V terminal apparatus MSR is shown. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

In the figure, the synchronization control unit 70 forms the multi-frame synchronization signal DDk at the timing of the multi-frame number "0", independently of the multi-frame timing of the received signal.
Is output to the data multiplexer 79 and the delay amount detector 87.

The delay amount detector 87 detects the time from when the multi-frame detection signal DD1 output from the synchronization units 73 and 74 is detected to when the multi-frame synchronization signal DDk output from the synchronization control unit 70 is detected. , Bit clock CPb is detected as the number of bits, and the detection result is output as a delay amount detection value DLd.

This delay amount detection value DLd is transferred to the system control unit 60 via the multiplexing / demultiplexing control unit 49, whereby the system control unit 60 sets the value corresponding to the input delay amount detection value DLd. , Is displayed on the display device 61 as the delay amount in the current communication state.

FIG. 20 shows the slave AV terminal device SLV1.
~ Shows a configuration example of the SLVm multiplexing / demultiplexing control device 45. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

In the figure, the delay circuit 88 includes a multiplexer / multiplexer.
The delay amount setting value DLs is added from the separation control unit 49, and when the delay circuit 88 receives the multi-frame detection signal DD1 output from the synchronizing units 73 and 74, it corresponds to the delay amount setting value DLs from the input timing. The multi-frame timing signal DDm is output at the timing when the number of bits of the bit clock CPb has passed.

With the above configuration, the master AV terminal device MSR
When the call setting operation is performed and the data transmission operation using the two information channels is started, the multiplexing / separation control unit 49 of the master AV terminal MSR delays the delay output from the multiplexing / separation control apparatus 45. Enter the quantity detection value DLd,
Transfer to the system control unit 60.

As a result, the system control unit 60 displays the value corresponding to the input delay amount detection value DLd on the display device 61 as the delay amount in the current communication state.

The operator who confirms this display notifies the operator of the slave AV terminal devices SLV1 to SLVm of the displayed delay amount, and each operator of the slave AV terminal devices SLV1 to SLVm notifies the input device 59 of its own terminal. Use to input the notified delay amount.

Thus, each slave AV terminal device SL
The system control unit 60 of V1 to SLVm outputs the delay amount setting value DLs corresponding to the input delay amount to the multiplexing / demultiplexing control device 45 via the multiplexing / demultiplexing control unit 49.

Accordingly, each slave AV terminal device SL
The value of the delay amount setting value DLs input to the delay circuit 88 of the multiplexing / separation control device 45 for V1 to SLVm is the master A
Multiframe detection signal DD in V terminal device MSR
From the detection timing of 1 to the multi-frame synchronization signal DDk
It becomes a value corresponding to the delay time until the detection timing of
As a result, each slave AV terminal device SLV1 to SLVm
The frame timings of the transmission signals TD1 and TD2 output from the same match the frame timings of the transmission signals TD1 and TD2 output from the master AV terminal device MSR.

FIG. 21 shows the configuration of a home station of a video conference system according to another embodiment of the present invention. In addition,
In the figure, the same parts as those in FIG. 10 and the corresponding parts are designated by the same reference numerals.

In the figure, the master AV terminal device MSR
From the above, the timing signal TMt representing the multi-frame number "0" of the transmission signal is the slave AV terminal device SL.
It is output to V1 to SLVm, and the slave AV terminal devices SLV1 to SLVm set the timing of the multi-frame number “0” of the transmission signal of the self terminal in synchronization with the timing signal TMt.

FIG. 22 shows the master AV terminal device M of FIG.
The structural example of SR is shown. In addition, in FIG.
The same reference numerals are given to the same portions as 2 and the corresponding portions.

In the figure, the multiplexing / demultiplexing control unit 45
From the above, the timing signal TM is output at the timing of the multi-frame number "0" of the transmission signal. This timing signal TM is transmitted to the slave AV terminal devices SLV1 to SLVm via the output circuit 90.
It is output as t.

FIG. 23 shows the master AV terminal device M of FIG.
An example of the configuration of the SR multiplexing / demultiplexing control device 45 is shown. In the figure, the same parts as those in FIG. 13 and corresponding parts are designated by the same reference numerals.

In the figure, the synchronization control unit 70 independently performs the synchronization operation, and at the timing of the multiframe number "0" in the operation, the multiframe synchronization signal DDl is generated.
And the multi-frame synchronization signal DD1 is added to the data multiplexing unit 79 and is output to the external device as the timing signal TM.

The slave AV terminal devices SLV1 to SLV1 of FIG.
The SLVm has the same configuration as the AV terminal device shown in FIG. 12, and a configuration example of the multiplexing / demultiplexing control device 45 thereof is shown in FIG.
Shown in. In the figure, the same parts as those in FIG. 13 and corresponding parts are designated by the same reference numerals.

In the figure, the master AV terminal device MSR
The timing signal TMt added thereto is applied to the data multiplexing unit 79 as a multi-frame synchronization signal, whereby the data multiplexing unit 79 causes the data multiplexing unit 79 to perform data multiplexing in the multiplexing / separation control unit 45 of the master AV terminal device MSR. The conversion section 79 operates at the same frame timing.

As a result, each slave AV terminal device SLV
The frame timings of the transmission signals TD1 and TD2 output from 1 to SLVm match the frame timings of the transmission signals TD1 and TD2 output from the master AV terminal device MSR.

FIG. 25 shows the structure of a home station according to another embodiment of the present invention. In addition, in FIG.
The same parts and corresponding parts are designated by the same reference numerals.

In this embodiment, the master AV terminal device MS
The R and the slave AV terminal devices SLV1 to SLVm are connected via a local area network LAN, and various information is exchanged using this local area network LAN.

In this case, the local area network L
As shown in FIG. 26, the signal format of the information exchanged via the AN (hereinafter referred to as command data) represents the destination identification information for designating the receiver of this command data, and the terminal that has transmitted this command data. It is composed of sender identification information, command identification information indicating a command type, and additional information indicating additional information necessary for the command.

The command identification information consists of a 2-digit hexadecimal number, and FIG. 27 shows an example of the relationship between the command type and the command identification information.

In this case, the data 41H (H represents a hexadecimal number; the same applies hereinafter) represents a "transmission permission" command for passing the transmission right to the terminal device of the identification information set in the additional information, and the data 42H is the additional data. A "delay amount notification" command that specifies that the value set in the information is set as the delay time from the reception of the multiframe number "0" of the reception signal to the output of the transmission signal of the multiframe number "0" Represents

The signal format of the command data is not limited to this. In addition, the types of the above-mentioned command types only show the parts according to the present embodiment, and it is possible to provide many types of commands (for example, history saving of terminal state).

FIG. 28 shows the master AV terminal device MSR and the slave AV terminal devices SLV1 to SL shown in FIG.
The structural example of Vm is shown. In addition, in FIG.
The same reference numerals are given to the same portions as 2 and the corresponding portions.

In the figure, the LAN interface circuit 91 is connected via a local area network LAN.
It realizes functions for exchanging various data (signal transmission / reception function, protocol function, etc.),
It is connected to the system control unit 60.

In this embodiment, the multiplexing / demultiplexing control device 45 is the same as that shown in FIG. 13, whereby the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm are provided. The frame timings of the transmission signals are set to be the same.

That is, in this case, the multiframe number "0" is transmitted at the timing when the delay time corresponding to n bits of the bit clock CPb has elapsed after the multiframe number "0" of the received signal was detected. The signal is output.

Also, in this embodiment, the master AV terminal device MSR to the slave AV terminal devices SLV1 to SLVm.
On the other hand, the transmission / reception of the transmission right is notified using the local area network LAN, and a processing example of the master AV terminal device MSR in that case is shown in FIG.

In the figure, the master AV terminal device MSR
Monitors whether the input device 59 is operated to request switching of the transmission terminal from the operator (NO loop of decision 201), and the operator of the master AV terminal device MSR (that is, chairperson or proceedings person). Performs an operation to pass the transmission right to the transmission terminal of the speaker (including himself) in order to change the speaker, the result of judgment 201 is YE.
In S, the master AV terminal device MSR creates command data of the "transmission permission" command to be sent out on the local area network LAN (process 202).

In this case, specific terminal identification information for designating all terminals is set in the destination identification information, terminal identification information representing the own terminal is set in the source identification information, and command identification information is set in the command identification information. The data 41H representing the "permit transmission" command is set, and the terminal identification information representing the newly designated transmitting terminal is set in the additional information.

Then, the created command data is changed to LA
The data is sent to the local area network LAN via the N interface circuit 91 (process 203).

On the other hand, the slave AV terminal devices SLV1 to SLV1.
Upon receiving the command data from the local area network LAN, the LVm performs the processing shown in FIG.

That is, the slave AV terminal device SLV1
~ SLVm is monitoring reception of command data from the local area network LAN (decision 2).
11 NO loop), local area network LA
When the command data is received from N, the result of judgment 211 is Y
When it becomes ES, it is checked whether the command data is a "transmission permitted" command (decision 212).

When the result of judgment 212 is YES, it is checked whether or not the terminal identification information set in the additional information matches the terminal identification information of the self terminal (decision 21).
3) When the result of determination 213 is YES, it is determined that the own terminal has acquired the transmission right, and the data transmission permission state is set in the multiplexing / separation control unit 45 via the multiplexing / separation control unit 49. (Process 214).

When the result of the judgment 213 is NO, it is judged that the own terminal does not acquire the transmission right, and the data transmission disabled state is transmitted via the multiplexing / separation control unit 49 to the multiplexing / separation control unit 45. Is set (step 215).

If the received command data is other than the "transmission permitted" command and the result of the determination 212 is NO, the process corresponding to the received command data is performed (process 216).

Thus, the master AV terminal device MS
R "permits transmission" for the terminal device that newly acquires the transmission right
Each slave AV terminal device SLV1 to SL via the local area network LAN specified by the command.
When Vm is notified, the slave AV specified at that time
The terminal devices SLV1 to SLVm start transmitting a transmission signal at the timing of the next multi-frame number “0” after receiving the command data, and the other slave AV terminal devices SLV1 to SLVm execute the command. After receiving the data, the transmission of the transmission signal is stopped from the timing of the next multi-frame number "0".

When the master AV terminal device MSR acquires the transmission right, the master AV terminal device MSR
After transmitting the command data, transmission of the transmission signal is started at the timing of the next multi-frame number "0". Further, when the transmission right is transferred from the master AV terminal device MSR to the other slave AV terminal devices SLV1 to SLVm, the master AV terminal device MSR sends the command data and then the next multiframe number “0” is sent. The transmission of the transmission signal is stopped at the timing "."

As described above, in this embodiment, since the transmission right is notified via the local area network LAN, the slave AV when the transmission right is moved.
The operator's trouble of the terminal devices SLV1 to SLVm becomes unnecessary.

By the way, in the above-described embodiment, the multi-frame number "0" of the received signal is detected at the timing when the delay time corresponding to n bits of the bit clock CPb elapses after the detection of the multi-frame number "0". Although the transmission signal is transmitted, the master AV terminal device MSR
The delay time from the detection of the multi-frame number “0” of the received signal to the transmission of the transmission signal of the multi-frame number “0” in the slave AV terminal devices SLV1 to SLV1.
You may make it set to LVm.

In this case, the configuration of the multiplexing / demultiplexing control device 45 of the master AV terminal device MSR is the same as that of FIG. 19, and the slave AV terminal devices SLV1 to SLV are the same.
The configuration of the multiplexing / demultiplexing control device 45 for m is the same as that shown in FIG.

In this case, FIG. 31 shows a processing example when the master AV terminal device MSR notifies the slave AV terminal devices SLV1 to SLVm of the delay time.

First, when the call connection with the partner station is completed, the master AV terminal MSR waits until the frame synchronization of the information channel is established (NO loop of decision 220), and the establishment of the synchronization is completed. If the result is YES, the delay amount detection value DLd output from the multiplexing / demultiplexing control device 45 is input via the multiplexing / demultiplexing control unit 49 (process 221), and the local area network L
Command data of the "delay amount notification" command sent by the AN is created (process 222).

In this case, the destination identification information is set to specific terminal identification information for designating all terminals, the source identification information is set to the terminal identification information representing the own terminal, and the command identification information is set to the command identification information. The data 42H representing the "delay amount notification" command is set, and the input delay amount detection value DLd is set as the additional information.

Then, the created "delay amount notification" command is sent to the local area network LAN via the LAN interface circuit 91 (process 223).

Note that the master AV terminal device MSR performs the same processing as in FIG. 29 when the transfer of the transmission right is designated, as in the above-described embodiment.

FIG. 32 shows the local area network L.
An example of processing performed by the slave AV terminal devices SLV1 to SLVm when command data is received via the AN is shown.

Slave AV terminal devices SLV1 to SLVm
Monitors the reception of command data via the local area network LAN (NO loop of decision 231). When the command data is received and the result of decision 231 is YES, the received command data is " Check whether it is a "delay amount" command (decision 23
2).

When the result of determination 232 is YES, the value set in the additional information of the command data is set to the delay amount set value D via the multiplexing / separation control unit 49.
The multiplexing / demultiplexing control device 45 is notified as Ls (process 233).

Thus, the slave AV terminal device SLV
1 to SLVm, the delay time from the detection of the multi-frame number “0” of the received signal to the transmission of the transmission signal of the multi-frame number “0” becomes equal to the delay time in the master AV terminal device MSR, AV terminal device MSR and slave AV terminal devices SLV1 to SL
The synchronization timings of the Vm transmission signals match.

When the received command data is not the "delay amount notification" command and the result of judgment 232 is NO, it is checked whether or not the received command data is the "transmission permission" command (decision 234). ..

When the result of judgment 234 is YES, it is checked whether or not the terminal identification information set in the additional information matches the terminal identification information of the self terminal (decision 23).
5) When the result of determination 235 is YES, it is determined that the own terminal has acquired the transmission right, and the data transmission permission state is set in the multiplexing / separation control unit 45 via the multiplexing / separation control unit 49. (Process 236).

Further, when the result of the judgment 235 is NO, it is judged that the own terminal does not acquire the transmission right, and the data transmission disabled state is transmitted via the multiplexing / separation control unit 49 to the multiplexing / separation control unit 45. Is set (step 237).

When the received command data is other than the "delay amount notification" command or the "transmission permission" command and the result of the judgment 234 is NO, the process corresponding to the received command data is performed (process 23).
8).

The master AV terminal device MSR and the slave AV terminal devices SLV1 to SLV in this embodiment.
The operation of moving the transmission right of Vm is the same as that of the above-described embodiment.

FIG. 33 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 25 and the corresponding parts are designated by the same reference numerals.

In this embodiment, the master AV terminal device MS
R and the slave AV terminal devices SLV1 to SLVm are connected via the local area network LAN, and the timing of the multiframe number "0" of the transmission signal from the master AV terminal device MSR to each slave AV terminal device SLV1 to SLVm. Is output as a timing signal TMt.

[0209] The master AV terminal device M in this embodiment
The structure of SR is shown in FIG. In addition, in FIG.
The same parts as those of FIG. 8 and the corresponding parts are denoted by the same reference numerals. The configuration of the slave AV terminal devices SLV1 to SLVm in this embodiment is the same as that of FIG.

In the figure, the multiplexing / demultiplexing control unit 45
From the above, the timing signal TM is output at the timing of the multi-frame number "0" of the transmission signal. This timing signal TM is transmitted to the slave AV terminal devices SLV1 to SLVm via the output circuit 90.
It is output as t.

The configuration of the multiplexing / demultiplexing control device 45 of the master AV terminal device MSR in this embodiment is shown in FIG.
Same as that of the slave AV terminal device SL.
The configuration of the multiplexing / demultiplexing control device 45 for V1 to SLVm is the same as that of FIG.

Also in this embodiment, the master AV terminal device M is connected via the local area network LAN.
As a method of instructing the slave AV terminal devices SLV1 to SLVm from the SR to acquire / relinquish the transmission right, the same method as the above-described embodiment can be used (see FIGS. 29 and 30).

In the above-mentioned embodiment, the case where a wired local area network LAN is used as the local area network LAN has been described, but a wireless local area network LAN can also be used. In that case, since the delay amount of the signal in the local area network LAN becomes almost 0, for example, from the master AV terminal device MSR to the slave AV terminal device SLV.
1 to SLVm, a timing signal representing the timing of the multi-frame number "0" is transmitted via the local area network LAN, and the slave AV terminal devices SLV1 to SLVm transmit the multi-frame at the timing matching the timing signal. By transmitting the transmission signal of the number “0”, the frame timings of the transmission signals of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm can be matched.

FIG. 35 shows a system configuration of a home station according to still another embodiment of the present invention.

In the figure, the network control terminal device 92
It terminates the SDN basic interface, and is connected to the line interface circuit 94 via the transformer 93.

The line interface circuit 94 is an ISDN.
Layer 1/2 by separating the received signal of the basic interface
In addition to outputting to the control device 95, the transmission signal output from the layer 1/2 control device 95 is sent to the ISDN basic interface.

The layer 1/2 control device 95 performs signal control of layers 1 and 2 of the ISDN basic interface, and is 2 multiplexed in the transmission / reception signal.
It has a function of separating / combining signals of one information channel and one signal channel, and the signal SDc on the signal channel is output to the plurality of AV terminal devices ATE1 to ATEm.

Further, the reception signals RD1 of the B1 channel and the reception signal RD2 of the B2 channel, the bit clock CPb representing the bit timings of the reception signals RD1 and RD2, and the reception signal RD1, which are separated by the layer 1/2 control device 95. The octet clock CPo representing the octet timing of the RD2 is output to each of the AV terminal devices ATE1 to ATEm.

The B1 channel transmission signal TD1 and the B2 channel transmission signal TD2 output from each of the AV terminal devices ATE1 to ATEm are added to a selection circuit 96 and a selection circuit 97, respectively.

Based on the selection signal SLa output from the control unit 98, the selection circuits 96 and 97 select the AV
To select the transmission signal TD1 and the transmission signal TD2 output from the terminal devices ATE1 to ATEm,
Transmission signal TD1 and transmission signal TD selected respectively
2 is output to the layer 1/2 control device 95 as the transmission signal TD1a and the transmission signal TD2a. Further, the timing of switching the selected transmission signals TD1 and TD2 is performed at the head of one of the sub-multiframes as described above. This sub-multiframe timing corresponds to one of the AV terminal devices ATE1 to ATE.
It is output from m to the selection circuits 96 and 97 (not shown).

The operation display section 99 is used for the AV terminal device ATE1.
Among ATEm, the one that gives the transmission right is selected and displayed, and the selected state is displayed. The operation signal is output to the control unit 98, and the display signal is added from the control unit 98.

The control unit 98 controls the designated AV terminal device AT based on the operation signal output from the operation display unit 99.
A selection signal SLa for selecting E1 to ATEm is formed and output to the selection circuits 96 and 97, and a display signal for displaying the selected state is formed and output to the operation display unit 99.

FIG. 36 shows the AV terminal devices ATE1 to ATE.
The structural example of m is shown. In addition, in FIG.
The same parts and corresponding parts are designated by the same reference numerals.

In the figure, the D channel layer 3 control unit 44 exchanges the signal SDc on the signal channel with the layer 1/2 control device 95, and performs multiplexing / demultiplexing.
The separation control device 45 includes reception signals RD1 and RD2 output from the layer 1/2 control device 95 and a bit clock C.
Pb and the octet clock CPo are added, and the transmission signals TD1 and TD2 output from the multiplexing / demultiplexing control unit 45 are output to the selection circuits 96 and 97, respectively.

Here, each of the AV terminal devices ATE1 to ATE
As a method of matching the frame timing of the transmission signal of m, the transmission signal of the multi-frame number "0" is obtained when a time corresponding to n bits of the bit clock CPb has passed from the timing of the multi-frame number "0" of the reception signal. 13 is used as the multiplexing / demultiplexing control unit 45, the method shown in FIG. 13 can be used.

With the above configuration, when performing videoconference communication between this home station and the partner station, the chair of the conference or the proceedings person operates the operation display unit 99 to display, for example, the AV terminal device ATE1. Select.

As a result, the control unit 98 outputs the selection signal SLa for selecting the AV terminal device ATE1 and selects the transmission signals TD1 and TD2 of the AV terminal device ATE1 by the selection circuit 9.
6 and 97 respectively, so that the transmission signals TD1 and TD2 of the AV terminal device ATE1 are changed to the transmission signal TD.
1a and TD2a are added to the layer 1/2 control device 95, respectively, and the communication operation by the AV terminal device ATE1 becomes possible.

At the same time, the control unit 98 forms a display signal indicating that the AV terminal device ATE1 is selected and outputs it to the operation display unit 99, whereby the operation display unit 99 displays the AV signal. It is displayed that the terminal device ATE1 is in the selected state.

Upon confirming this display, the chairperson or the person in charge of proceedings operates the AV terminal device ATE1 to make a call to the opposite station, whereby the call setting procedure between the AV terminal device ATE1 and the opposite station is performed. Then, two information channels are sequentially established, and frame synchronization in each information channel is detected and established.

On the other hand, the other AV terminal devices ATE2 to ATE2
The ATEm receives the reception signals RD1 and RD2 output from the layer 1/2 control device 95, and each of the AV terminal devices ATE2 to ATEm independently outputs the transmission signals TD1 and TD2.

Thus, the AV terminal devices ATE2 to AT
The same audio signal as that of the AV terminal device ATE1 is output to Em, and a video is displayed and output.

[0232] Then, for example, when a conference participant who is using the AV terminal device ATE2 requests a speech and the chairperson or the proceedings officer accepts it, the chairperson or the proceedings officer operates the operation display section 99. Then, the AV terminal device AT
Select E2.

As a result, the control unit 98 outputs the selection signal SLa for selecting the AV terminal device ATE2, whereby the selection circuits 96 and 97 select the transmission selected immediately after the start timing of the sub-multiframe. Signals TD1, T
D2 is switched from that of the AV terminal device ATE1 to that of the AV terminal device ATE2.

As a result, the transmission signals TD1 and TD2 of the AV terminal device ATE2 are set to the state of being added to the layer 1/2 control device 95 as the transmission signals TD1a and TD2a. Further, the synchronization state of the transmission signals TD1 and TD2 is not lost before and after the switching of the transmission signals TD1 and TD2.

At the same time, the control unit 98 forms a display signal indicating that the AV terminal device ATE2 is selected and outputs it to the operation display unit 99, whereby the operation display unit 99 displays the AV signal. It is displayed that the terminal device ATE2 is in the selected state. In this way, the transmission signal TD from the AV terminal device ATE2 of the participant who asked to speak
1, TD2 are transmitted to the partner station, and the utterance content of the speaker is output to the partner station.

In this way, in this embodiment, the transmission / reception operation is performed in a state where the AV terminal devices ATE1 to ATEm are synchronized with each other, and the transmission signal of any one of the AV terminal devices ATE1 to ATEm is valid. Output to the station.

By the way, each of the AV terminal devices ATE1 to AT
As a method of matching the frame timings of the Em transmission signals, for example, a time difference between the multi-frame number “0” of the reception signal and the multi-frame number “0” of the transmission signal in the specific AV terminal device ATE1 is detected, and other than that, A method of matching the time difference between the multiframe number “0” of the AV terminal devices ATE2 to ATEm and the multiframe number “0” of the transmission signal with the detected time difference can be used. AV terminal device ATE1
19 is used as the multiplexing / demultiplexing control device 45 of the other AV terminal devices ATE2 to ATEm.
20 is used as the multiplexing / demultiplexing control device 45 of FIG.

The value of the delay time displayed on the display device 61 of the AV terminal device ATE1 when the frame synchronization of the call setting and the information channel is detected / established by the specific AV terminal device ATE1 is completed. Are input by the users of the other AV terminal devices ATE2 to ATEm using the input device 59.

Thus, the AV terminal devices ATE2 to AT
In Em, the system control unit 60 sets the input delay time value in the multiplexing / demultiplexing control unit 45 via the multiplexing / demultiplexing control unit 49, and as a result, all AV terminal devices AT
In E1 to ATEm, the frame timings of the transmission signals match.

FIG. 37 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 35 and the corresponding parts are designated by the same reference numerals.

In the figure, the control unit 98 generates a timing signal TMm at a time interval (= 2.56 seconds) corresponding to 16 multi-frame intervals.
Mm is added to each of the AV terminal devices ATE1 to ATEm.

FIG. 38 shows AV terminal devices ATE1 to ATE.
The structural example of m is shown. Incidentally, in FIG.
The same or corresponding parts are designated by the same reference numerals.

In the figure, the multiplexing / demultiplexing control unit 45
Is the timing signal TMm output from the control unit 98.
Has been added. Further, in this case, as the multiplexing / demultiplexing control device 45, the one having the same configuration as in FIG. 24 is used.

That is, in this embodiment, the control unit 98 generates the timing signal TMm for defining the timing of the multiframe number "0", and the AV terminal device ATE1 is generated.
~ Each AV terminal device A by adding to ATEm
The frame timings of the transmission signals of TE1 to ATEm are matched.

The AV terminal devices ATE1 to ATE1 in this case
Since the ATEm selecting operation and the communication operation are the same as those shown in FIG. 35, the description thereof will be omitted.

FIG. 39 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 35 and the corresponding parts are designated by the same reference numerals.

In the figure, transmission signal synchronization units 101, 1
02 is set so that the timing of the multiframe number “0” of the transmission signals TD1 and TD2 output from the AV terminal device ATE1 matches the timing of the multiframe number “0” of the other AV terminal devices ATE2 to ATEm. , The transmission signal TD of the AV terminal devices ATE2 to ATEm
1 and TD2 are buffered and output to the selection circuits 96 and 97.

Therefore, the AV terminal devices ATE1 to AT
The transmission signals TD1 and TD2 of Em are output to the selection circuits 96 and 97 in a state where the timing is adjusted so that the frame timings match.

Further, in this case, the AV terminal device ATE
1 to ATEm can output the transmission signals TD1 and TD2 at independent timings, and FIG. 40 shows an example of the multiplexing / demultiplexing control device 45 applied to the AV terminal devices ATE1 to ATEm. In addition, in FIG.
The same parts as those in 3 are designated by the same reference numerals.

In the figure, the synchronization control unit 70 independently performs the synchronization operation, and at the timing of the multiframe number "0" in the operation, the multiframe synchronization signal DDl is generated.
And the multi-frame synchronization signal DD1 is added to the data multiplexing unit 79.

The AV terminal devices ATE1 to ATE1 in this case
Since the ATEm selecting operation and the communication operation are the same as those shown in FIG. 35, the description thereof will be omitted.

FIG. 41 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 10 and corresponding parts are designated by the same reference numerals.

In the figure, the master AV terminal device MTR
And the slave AV terminal devices SLA1 to SLAm are connected to the passive bus 21, and the master AV terminal device MTR to the slave AV terminal devices SLA1 to SLAm.
Is added with a reception signal RD on two information channels, a bit clock CPb and an octet clock CPo, and transmission signals on two information channels from the slave AV terminal devices SLA1 to SLAm to the master AV terminal device MTR. TD has been added.

FIG. 42 shows a configuration example of the master AV terminal device MTR. In the figure, the same parts as those in FIG. 12 and corresponding parts are designated by the same reference numerals.

In the figure, a socket 105 connects this master AV terminal device MTR to the passive bus 21, and receives signals RD1 and RD2 output from the layer 1/2 control device 43, bit clock CPb and octet. The clock CPo is added to the multiplexing / demultiplexing control unit 45, and also the slave AV terminal units SLA1 to SLA1.
It is output to SLAm.

The transmission signals TD1 and TD2 output from the multiplexing / demultiplexing control device 45 are the transmission signal selection circuit 1
06, and the transmission signal selection circuit 1
The transmission signal TD output from the slave AV terminal devices SLA1 to SLAm is added to 06.

FIG. 43 shows the slave AV terminal device SLA1.
~ Shows a configuration example of SLAm. In the figure, the same parts as those in FIG. 42 and the corresponding parts are designated by the same reference numerals.

In the figure, the signal switch 107 includes a reception signal RD1 output from the layer 1/2 control device 43.
RD2, bit clock CPb, and octet clock CPo, and reception signals RD1 and RD2 output from the master AV terminal device MTR, bit clock CPb,
Also, by switching the octet clock CPo, the multiplexing / demultiplexing control unit 45 receives the received signals RD1 and RD, respectively.
2, the bit clock CPb and the octet clock CPo, and the transmission signals TD1 and TD2 output from the multiplexing / demultiplexing control device 45 to either the layer 1/2 control device 43 or the master AV terminal device MTR. It is output. When the layer 1/2 control device 43 is selected, the signal SDc on the signal channel output from the layer 1/2 control device 43 is output.
With the D channel layer 3 control unit 44.

In addition, in this embodiment, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLA are provided.
As the multiplexing / demultiplexing control device 45 for m, the one shown in FIG. 13 is used.

With the above configuration, when the video conference communication is performed between the home station and the partner station, the master AV terminal device M
A TR user (for example, a chairperson or a proceedings person) sets his / her terminal as a transmission terminal, and users of the slave AV terminal devices SLA1 to SLAm are set to connect to the master AV terminal device MTR. To do.

As a result, in the master AV terminal device MTR, the system controller 60 causes the transmission signal selection circuit 106 to output the transmission signal T output from the multiplexing / demultiplexing control device 45.
D1 and TD2 are selected and output to the layer 1/2 control device 43, whereby the data communication operation by the master AV terminal device MTR becomes possible.

The slave AV terminal devices SLA1 to S
In the LAm, the system control unit 60 selects the master AV terminal device MTR by the signal switch 107, thereby
The multiplexing / demultiplexing control device 45 is provided to the reception signal RD1 from the master AV terminal device MTR via the signal switch 107.
RD2, bit clock CPb, and octet clock CPo are added, and transmission signals TD1 and TD2 output from multiplexing / demultiplexing control device 45 are output to master AV terminal device MTR via signal switch 107. ..

At this time, the D channel layer 3 control unit 44 of the slave AV terminal devices SLA1 to SLAm.
Since the signal SDc is not exchanged between the slave AV terminal device SLA and the layer 1/2 control device 43.
1 to SLAm cannot perform independent call setup operations.

In this state, the master AV terminal device MTR calls the partner station, a call setting operation is performed, two information channels are established, and frame synchronization detection / establishment of the two information channels is performed.

On the other hand, the slave AV terminal devices SLA1 to SLA
In LAm, the reception operation of the reception signal RD is performed, and as described above, the transmission operation is independently performed at the same frame timing as the master AV terminal device MTR. However, in this case, only the transmission signal TD of the master AV terminal device MTR is selected and output to the passive bus 21.

Therefore, the transmission operation by the master AV terminal device MTR is effectively performed, and the slave AV
In the terminal devices SLA1 to SLAm, the same sound as that received by the master AV terminal device MTR is output, and the video is displayed and output.

In this state, for example, the user of the slave AV terminal device SLA1 asks for a message and is accepted, and the user of the master AV terminal device MTR makes a slave AV terminal device MLA.
When an operation input is made to switch to the terminal device SLA1,
The system control unit 60 of the master AV terminal device MTR uses the transmission signal selection circuit 106 at the start timing of the sub-multiframe to select the transmission signal TD to be selected from the multiplexing / demultiplexing control device 45 to the transmission signal TD of the slave AV terminal device SLA1. Switch to.

As a result, the transmission signal TD of the slave AV terminal device SLA1 used by the speaker changes to the passive bus 2
It is output to 1 and is received by the partner station.

In this way, the master AV terminal device MTR and the slave AV terminal device SLA are selected according to the speaker.
1 to SLAm transmission signals TD, the transmission signal selection circuit 10
By selecting with 6, it is possible to transmit the message of the user of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm to the partner station.

In addition to the video conference communication as described above, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm can also independently perform the communication operation.

In this case, the slave AV terminal device SLA1
The user of ~ SLAm uses the input device 59 to command to connect to the passive bus 21.

Thus, the slave AV terminal device SLA
The control unit 60 of 1 to SLAm causes the signal switch 107 to receive the reception signals RD1 and RD2 output from the layer 1/2 control device 43, the bit clock CPb, and the octet clock CPo to the multiplexing / demultiplexing control device 45. At the same time, the transmission signals TD1 and TD2 output from the multiplexing / demultiplexing controller 45 are added to the layer 1/2 controller 43
Add to. At the same time, the signal SDc on the signal channel between the layer 1/2 control device 43 and the D channel layer 3 control unit 44 is made ready for exchange.

As a result, the slave AV terminal device SL
A1 to SLAm are in a state where the call setting operation and the data transmission operation can be performed independently.

By the way, as a method of matching the frame timings of the transmission signals of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm, for example, the multi-frame number "0" of the reception signal in the master AV terminal device MTR is transmitted. The time difference of the multi-frame number "0" of the signal is detected and the slave AV terminal device SL is detected.
A method of matching the time difference between the multi-frame number "0" of A1 to SLAm and the multi-frame number "0" of the transmission signal with the detected time difference can be used. In that case, the master AV terminal device MTR The multiplexer / demultiplex controller 45 shown in FIG. 19 is used, and the slave A
20 is used as the multiplexing / demultiplexing control device 45 of the V terminal devices SLA1 to SLAm.

Then, the master AV terminal device MTR performs the call setting and the information channel frame synchronization detection / establishment operation, and the value of the delay time displayed on the display device 61 of the master AV terminal device MTR when the frame synchronization is completed. Are input by the users of the slave AV terminal devices SLA1 to SLAm using the input device 59.

As a result, the slave AV terminal device SLA
In 1 to SLAm, the system control unit 60 sets the input delay time value in the multiplexing / demultiplexing control unit 45 via the multiplexing / demultiplexing control unit 49, and as a result, the master AV terminal device MTR and slave AV terminal devices SLA1 to SL
At Am, the frame timings of the transmission signals match.

FIG. 44 shows a configuration example of the master AV terminal device MTR according to still another embodiment of the present invention.
In the figure, the same parts as those in FIG. 42 are designated by the same reference numerals. Further, this embodiment is applied to a home station having the same system configuration as that shown in FIG.

In the figure, the transmission signal synchronization selection circuit 10
8 indicates that the timing of the multi-frame number "0" of the slave AV terminal devices SLA1 to SLAm matches the timing of the multi-frame number "0" of the transmission signals TD1 and TD2 output from the multiplexing / demultiplexing control device 45. In addition to buffering the transmission signals TD of the slave AV terminal devices SLA1 to SLAm, the transmission signals TD1 and TD2 output from the multiplexing / demultiplexing control device 45 and the transmission signals TD output from the slave AV terminal devices SLA1 to SLAm. To select the layer 1/2 control device 4
3 is output.

Further, in this case, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm.
Are transmission signals TD1 and T at independent timings.
D2 can be output, and therefore, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLA
The multiplexer / demultiplex controller 45 applied to the LAm is shown in FIG.
The same structure as shown in FIG. 0 can be used.

FIG. 45 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 41 and the corresponding parts are designated by the same reference numerals.

In this embodiment, the master AV terminal device MT
The timing signal TMm is generated at the timing of R having the multi-frame number "0", and the timing signal TMm is added to the slave AV terminal devices SLA1 to SLAm.

In this case, as the multiplexing / demultiplexing control device 45 of the master AV terminal device MTR, the same structure as that shown in FIG. 23 can be used, and the multiplexing of the slave AV terminal devices SLA1 to SLAm is possible. The conversion / separation control device 45 may have the same configuration as that shown in FIG.

Incidentally, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SL in this embodiment.
Since the operation of Am is the same as that shown in FIG. 41, its description is omitted.

By the way, in the above-mentioned embodiment, the home station directly connected to the ISDN basic interface has been described, but the present invention relates to the home station connected to the extension side basic interface of the private branch exchange. Can be similarly applied.

The configuration of each AV terminal device is as follows.
It is not limited to the above. Further, in the above description, description of parts that are not directly related to the present invention is omitted.

[0286]

As described above, according to the present invention,
Multiple I's connected to the same ISDN basic interface
Since the video conference system can be constructed by using the SDN audiovisual terminal device, the line cost of the entire video conference system can be reduced. Also, since each participant can occupy and use one ISDN audiovisual terminal device, an unfavorable situation that occurs during the proceedings of the proceedings, for example, camera sickness caused by frequent switching of camera angles, Since it is possible to eliminate the need for an unnatural posture for viewing a still image, the usability of the video conference system is improved and the effectiveness of the video conference system is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a video conference system according to an embodiment of the present invention.

FIG. 2 is a time chart showing an example of a call control procedure of an ISDN terminal device.

FIG. 3 is a schematic diagram showing an example of a signal format of a call setting signal.

FIG. 4 is a schematic diagram showing an example of a multi-frame structure.

FIG. 5 is a schematic diagram showing an example of a frame structure.

FIG. 6 is a schematic diagram illustrating a signal format of a frame synchronization signal.

FIG. 7 is a schematic diagram illustrating a signal format of a bit rate allocation signal.

FIG. 8 is a time chart for explaining a transmission order of frame data.

FIG. 9: TTC Recommendation JT-H. The time chart which shows the example of a procedure of 320.

FIG. 10 is a block diagram showing a system configuration of a home station according to an embodiment of the present invention.

FIG. 11 is a timing chart for explaining transmission signal switching timing.

12 is a block diagram showing an example of a configuration of a master AV terminal device and a slave AV terminal device of FIG.

13 is a block diagram showing an example of the multiplexing / demultiplexing control device of FIG.

FIG. 14 is a timing chart for explaining an output timing of a multi-frame number “0” of a transmission signal.

FIG. 15 is a flowchart showing a processing example at the start of transmission of the master AV terminal device.

FIG. 16 is a flowchart showing a processing example at the start of transmission by the slave AV terminal device.

FIG. 17 is a flowchart showing a processing example of a terminal switching operation during data transmission of a master AV terminal device and a slave AV terminal device.

FIG. 18 is a timing chart for explaining a transmission signal switching operation.

FIG. 19 is a block diagram showing a configuration example of a master AV terminal device according to another embodiment of the present invention.

FIG. 20 is a block diagram showing a configuration example of a slave AV terminal device according to another embodiment of the present invention.

FIG. 21 is a block diagram showing another embodiment of the system configuration of the home station according to the present invention.

22 is a block diagram showing a configuration example of the master AV terminal device of FIG. 21.

23 is a block diagram showing a configuration example of the slave AV terminal device of FIG. 21.

FIG. 24 is a block diagram showing still another configuration example of the slave AV terminal device of FIG. 21.

FIG. 25 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

FIG. 26 is a schematic diagram showing an example of a signal format of command data exchanged via a local area network.

FIG. 27 is a schematic diagram showing an example of command data.

FIG. 28 is a block diagram showing a configuration example of a master AV terminal device and a slave AV terminal device shown in FIG. 25.

29 is a flowchart showing a processing example of the master AV terminal device shown in FIG.

FIG. 30 is a flowchart showing a processing example of the slave AV terminal device shown in FIG. 25.

31 is a flowchart showing another processing example of the master AV terminal device shown in FIG. 25.

32 is a flowchart showing another example of processing of the slave AV terminal device shown in FIG.

FIG. 33 is a block diagram showing yet another embodiment of the system configuration of the home station according to the present invention.

34 is a block diagram showing a configuration example of the master AV terminal device shown in FIG.

FIG. 35 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

36 is a block diagram showing a configuration example of the AV terminal device of FIG. 35.

FIG. 37 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

38 is a block diagram showing a configuration example of the AV terminal device shown in FIG. 37.

FIG. 39 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

FIG. 40 is a block diagram showing a configuration example of a multiplexing / demultiplexing control device of the AV terminal device of FIG. 39.

FIG. 41 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

42 is a block diagram showing a configuration example of the master AV terminal device in FIG. 41. FIG.

43 is a block diagram showing a configuration example of the slave AV terminal device of FIG. 41.

FIG. 44 is a block diagram showing another configuration example of the master AV terminal device of FIG. 41.

FIG. 45 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

FIG. 46 is a schematic diagram showing a conventional example of a video conference system.

FIG. 47 is a schematic view showing another conventional example of a video conference system.

FIG. 48 is a schematic diagram showing a conventional example of the system configuration of a home station of a video conference system.

[Explanation of symbols]

MSR, MTR Master AV terminal device SLV1 to SLVm, SLA1 to SLAm Slave A
V terminal device 45 Multiplexing / demultiplexing control device 70 Synchronization control unit 78, 88 Delay circuit 87 Delay amount detection unit LAN local area network 91 Local area network interface circuit ATE1 to ATEm AV terminal device 95 Layer 1/2 control device 96, 97 Selection circuit 98 Control unit 100, 101 Transmission signal synchronization unit 106 Transmission signal selection circuit 107 Signal switcher 108 Transmission signal synchronization selection circuit

Claims (7)

[Claims] 1. A method of controlling a plurality of ISDN audiovisual terminal devices connected to a passive bus of the same ISDN basic interface, wherein each of the ISDN audiovisual terminal devices includes a transmission signal synchronizing means for synchronizing a transmission signal of the ISDN audiovisual terminal device. The transmission signal selecting means for selectively outputting the transmission signal of the ISDN audiovisual terminal device of the present invention to the passive bus effectively is provided, and the specific ISDN audiovisual terminal device performs the call setup / release procedure with the ISDN. The ISDN audiovisual terminal device receives a reception signal through a passive bus and outputs the reception information, while each ISD
A method for controlling an ISDN audiovisual terminal device, characterized in that the ISDN audiovisual terminal device that effectively outputs a transmission signal is selected by the transmission signal selecting means based on a transmission request from the N audiovisual terminal device. 2. A method of controlling a plurality of ISDN audiovisual terminals connected to a passive bus having the same ISDN basic interface, wherein each of the ISDN audiovisual terminals has a transmission signal synchronizing means for synchronizing the transmission signals of the ISDN audiovisual terminals. Each ISDN audiovisual terminal device is provided with a communication means for connecting an ISDN audiovisual terminal device and exchanging control information, and a specific ISDN audiovisual terminal device performs a call setup / release procedure with the ISDN. While receiving the reception signal through the passive bus and outputting the reception information, the specific ISDN is specified based on the transmission request of each ISDN audiovisual terminal device.
The audiovisual terminal device notifies each ISDN audiovisual terminal device through the communication means of a control signal designating an ISDN audio terminal device that effectively outputs a transmission signal, and the designated audiovisual terminal device transmits the transmission signal. A method for controlling an ISDN audiovisual terminal device, characterized in that 3. Layer 1 signal control means for separating and integrating a received signal and a transmitted signal on an ISDN basic interface,
The layer 1 is selected by selecting one of transmission signals output from a plurality of ISDN audiovisual terminal devices.
The transmission signal selecting means for outputting to the signal control means and the transmission signal synchronizing means for synchronizing the transmission signal of each ISDN audiovisual terminal device are provided, and a specific ISDN audiovisual terminal device establishes / sets a call with the ISDN.
While performing the release procedure, each ISDN audiovisual terminal device receives the reception signal output from the layer 1 signal control means and outputs the reception information, while sending a request for transmission from each ISDN audiovisual terminal device. Based on the above, the control method of the ISDN audiovisual terminal device is characterized in that the ISDN audiovisual terminal device which effectively outputs the transmission signal is selected by the transmission signal selecting means. 4. The transmission signal synchronization means converts the frame data of the transmission signal into a frame data of the transmission signal at a timing when a predetermined delay time has elapsed from the timing of detecting the frame synchronization signal included in the frame data forming the data transfer unit of the reception signal. The ISDN audiovisual terminal device according to claim 1, 2 or 3, wherein the output timing of the included frame synchronization signal is set. 5. The transmission signal synchronization means is configured to transmit the specific I
A delay time detecting means for detecting a delay time based on a difference between a frame sync signal detection timing of a received signal and an output timing of a frame sync signal of a transmitted signal in the SDN audiovisual terminal device, and the specific ISDN.
The delay time from the frame sync signal detection timing of the received signal to the output timing of the frame sync signal of the transmitted signal in the ISDN audiovisual terminal device other than the audiovisual terminal device is set to a time corresponding to the detected value of the delay time detecting means. The ISDN audiovisual terminal device according to claim 1, 2 or 3, further comprising delay time setting means. 6. The transmission signal synchronization means is configured to provide each I at a time interval corresponding to a frame repetition period of the transmission signal.
4. The ISDN audiovisual terminal device according to claim 3, wherein a synchronization signal is output to the SDN audiovisual terminal device. 7. The transmission signal synchronizing means is a specific ISD.
At the frame synchronization timing of the transmission signal output from the N terminal device, ISDN other than this specific ISDN terminal device
4. The ISDN audiovisual terminal device according to claim 3, wherein the frame synchronization timings of the transmission signals of the terminal device are matched.